Computational study of the Seebeck coefficient of one-dimensional composite nanostructures

Authors

Raseong Kim, Birck Nanotechnology Center, Purdue UniversityFollow
Mark S. Lundstrom, Purdue UniversityFollow

Abstract

The Seebeck coefficient (S) of composite nano-structures is theoretically explored within a self-consistent electro-thermal transport simulation framework using the non-equilibrium Green’s function method and a heat diffusion equation. Seebeck coefficients are determined using numerical techniques that mimic experimental measurements. Simulation results show that, without energy relaxing scattering, the overall S of a composite structure is determined by the highest barrier within the device. For a diffusive, composite structure with energy relaxation due to electron-phonon scattering, however, the measured Sis an average of the position-dependent values with the weighting factor being the lattice temperature gradient. The results stress the importance of self-consistent solutions of phonon heat transport and the resulting lattice temperature distribution in understanding the thermoelectric properties of a compositestructure. It is also clarified that the measured S of a composite structure reflects its power generation performance rather than its cooling performance. The results suggest that the lattice thermal conductivity within the composite structure might be engineered to improve the power factor over the bulk by avoiding the conventional trade-off between S and the electrical conductivity.

Comments

Copyright (2011) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Appl. Phys. 110, 034511 (2011) and may be found at http://dx.doi.org/10.1063/1.3619855. The following article has been submitted to/accepted by Journal of Applied Physics. Copyright (2011) Raseong Kim and Mark Lundstrom. This article is distributed under a Creative Commons Attribution 3.0 Unported License.

Date of this Version

2011

Published in:

Computational study of the Seebeck coefficient of one-dimensional composite nano-structures. Raseong Kim and Mark S. Lundstrom. J. Appl. Phys. 110, 034511 (2011)